Properly process getOwnPropertyDescriptor for elements on global proxy object.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 9911e1e3a3251620c68297902e4655875d6d9e86..e1a8954f50ef1e680a0f799ba3e6f165f6fdf53f 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -779,6 +779,12 @@ static MaybeObject* Runtime_GetOwnProperty(Arguments args) {
       }
 
       case JSObject::DICTIONARY_ELEMENT: {
+        if (obj->IsJSGlobalProxy()) {
+          Object* proto = obj->GetPrototype();
+          if (proto->IsNull()) return Heap::undefined_value();
+          ASSERT(proto->IsJSGlobalObject());
+          obj = Handle<JSObject>(JSObject::cast(proto));
+        }
         NumberDictionary* dictionary = obj->element_dictionary();
         int entry = dictionary->FindEntry(index);
         ASSERT(entry != NumberDictionary::kNotFound);